What are the recommendations for the use of reactive and vat dyes？

1 Reactive dyeing

In the continuous dyeing process, in order to prevent the reactive dyes from driving lightly when dyeing, add 5-10% of the total concentration to the tank according to different colors to control the front and back fading. According to the characteristics of the dyes, when discharging and normal dyeing in the trough, ensure that the flow tube is uniform and consistent to prevent inconsistent color fading before and after. Urea can be added to the dye solution to aid solubilization, and sodium alginate can be added to level the dye. When pre-drying the machine, ensure that the degree of dryness in the front and rear sides of the falling cloth is as consistent as possible. The temperature of the steam box is guaranteed to be 100～103℃, the time is 60～90s, the internal pressure U-tube (1～2cm, the steam time is not enough, or Inconsistent temperatures in the edges will cause color difference in the front and rear edges.

2 Vat dyeing

According to the characteristics of vat dyes, a certain amount (about 10%) of dye is added to the rear feed tank (fixing solution) during the initial start-up to prevent insufficient reducing gas in the steam box at the first start-up and continuous fall of dye into the feed tank. Before and after color. When dyeing, add 10%-15% water of the total concentration of the dye to each tank to control the front and back fading.

In addition, the dye is insoluble in water and is very easy to migrate. Therefore, adding TM-88 anti-migration agent to the dye solution is good for the color difference in the edge and level dyeing of the fabric. Dry evenly during drying, and try to use infrared heating drying room to dry. Don't rely too much on the drying cylinder to prevent migration and cause color difference.